The Rigado Gateway Vesta release of Beryllium 4.x will default to setting the float-abi option to hard. Prior to Beryllium 4.x the softfp option was used. The softfp or hard value is a compile time option that is set prior to building a Yocto image. These options are defined in the GNU gcc document.

The default depends on the specific target configuration. Note that the hard-float and soft-float ABIs are not link-compatible; you must compile your entire program with the same ABI, and link with a compatible set of libraries.

The important thing to note, is that any precompiled binaries built using soft or softfp ABI will no longer work without recompiling them using the float-abi=hard option. Fortunately, the Yocto build system takes care of this for you automatically as it builds the binary files. However, if you have added a precompiled binary to your Yocto build it will need to be recompiled using the float-abi=hard option.

Note

If you have a custom image that does not use precompiled binaries, binaries compiled outside of Yocto, this change will not require any action on your part. If you are using compiled binaries built outside of the Yocto build system, those binaries will need to be recompiled using the float-abi=hard option.

The option exist in Beryllium 4.0.0 to switch between using either the hard or softfp ABI option. To use the softfp option with Beryllium 4.x.x, add the following line to your build/conf/local.conf file:

DEFAULTTUNE_mx6ul = “cortexa7t-neon”

Using this variable will cause Yocto to rebuild the source files with the float-abi set to softfp. Also, the Vesta layers provided by Rigado will use the appropriate precompiled binaries that we provide.

Warning

Switching the ABI between hard and softfp will require a full image rebuild.

Linpack is a benchmarking tool that test the number of floating point operations a processor can execute in one second (FLOPS). Below is the linpack benchmark results using the different float-abi options on a Rigado Gateway:

float-abi

FLOPS

hard

71.2 Million

softfp

67.2 Million

soft

7.8 Million

Note

It would be extremely unlikely that float-abi would ever be set to soft on a Rigado Gateway.